1. Field of the Invention
The present invention relates to a meter system applicable to meters mounted in an automotive vehicle.
2. Background Art
A conventional vehicle-mounted meter is disclosed in Japanese Patent Application Laid-open No. 2003-194595. FIG. 8 is an exploded perspective view showing a construction of the conventional meter. The meter has a dial plate 101, a light guiding plate 102, a bearing plate 103, a fore cover 104, a circuit board 105, and a rear cover 106. The dial plate 101 is elongated in a transverse direction to comply with a combination meter including meters for vehicle speed, engine revolution speed, fuel quantity, and cooling water temperature, etc. The dial plate 101 is provided with a meter scale pattern 111a for vehicle speed, engine revolution speed, fuel quantity, and cooling water temperature, a winker indication pattern 111b, a warning indication pattern 111c, etc. The meter pattern 111a is provided for a speed meter, a tachometer, a fuel meter, and a water temperature meter. The light guiding plate 102 guides light emitted from a light source element to illuminate a rear face of the dial plate 101 for the speed meter and the fuel meter. The fore cover 104 is shaped like a saucer and transversely elongated to fit the dial plate 101. The fore cover 104 is combined with the rear cover 106 so as to sandwich the circuit board 105 therebetween.
The circuit board 105 has a transversely elongated shape in the same way as the dial plate 101. The circuit board 105 has a front face arranged with a plurality of LEDs (Light Emitting Diodes) 152 to supply light for a pointer 113 and electronic parts 151 including an IC chip. The circuit board 105 has a rear face arranged with a movement 153 turning the pointer 113. The movement 153 has a pointer shaft 153a penetrating through the circuit board 105 to extend forward. Similarly, another movement 153 (not shown) is provided for the fuel meter, the tachometer, and the water temperature meter respectively. The rear cover 106 has an elongated saucer shape like the fore cover 104.
FIG. 9 is a block diagram showing a general electric configuration of a meter mounted in an automotive vehicle. In FIG. 9, a vehicle-mounted combination meter 200 has a micro computer 201, input terminals 202 to 205, 206a to 206n, I/O (input/output) circuits 207 to 210, drivers 211, 216, 220, a speed meter 212, a tachometer 213, a fuel meter 214, a water temperature meter 215, LEDs 217a to 217n, an LCD (Liquid Crystal Display) 221, an EEPROM (Electrically Erasable Programmable Read-only Memory) 222, etc.
The micro computer 201 controls the combination meter 200 as a whole. The micro computer 201 receives vehicle speed signals (SPD) through the input terminals 202 and the I/O circuit 207. The micro computer 201 also receives engine revolution signals (TACHO) through the input terminal 203 and the I/O circuit 208. The micro computer 201 further receives signals of a remaining fuel quantity (FUEL) and a water temperature (TEMP) through the input terminals 204 and 205, an I/O circuit 209, and an A/D converter 201a. The micro computer 201 further receives various warning signals, operation signals (PRNDL) of an automatic shift lever, etc. via the input terminals 206a to 206n. 
The micro computer 201 controls the driver 211 to operate the speed meter 212, the tachometer 213, the fuel meter 214, and the water temperature meter 215 respectively in response to input signals of vehicle speed (SPD), engine revolution speed (TACHO), remaining fuel quantity (FUEL), and cooling water temperature (TEMP), so that each meter may indicate a value corresponding to each signal. Furthermore, the micro computer 201 controls the driver 216 to turn on or off the LEDs 217a to 217n in response to signals for various warning, automatic shift lever operation (PRNDL), etc.
Electric circuits for control of the micro computer 201 are incorporated in an integrated circuit board like the circuit board 105 shown in FIG. 8 to operate each meter. The circuits are desirably connected to the meters to operate them.
Meanwhile, for standardization of parts, another conventional in-vehicle combination meter has a control section such as a micro computer to control meters. The control section is separated from an indication section of vehicle speed, engine revolution speed, etc., and multiplex communication is applied for signal transmission between the control section and the indication section. Such combination meters are disclosed in Japanese patent preliminary publication No. H5-53367, Japanese patent application laid-open No. 2001-356031, and Japanese patent application No. 2002-142720.
FIG. 10 is an illustration showing a configuration of a vehicle mounted combination meter disclosed in Japanese patent preliminary publication No. H5-53367. The combination meter has a main body 301 and a control circuit section 302 which are separately constructed and disposed in the vehicle.
The combination meter main body 301 has a vehicle speed meter 311, an engine revolution speed meter 312, a cooling water temperature meter 313, a fuel meter 314, and a case 315 accommodating the meters. The vehicle speed meter 311, the engine revolution speed meter 312, the cooling water temperature meter 313, and the fuel meter 314 have cross-coil movements 311a to 314a, pointers 311b to 314b, dial plates 311c to 314c, and drive circuits 311d to 314d respectively. The drive circuits 311d to 314d are sequentially connected one another. The drive circuit 313d positioned at one end of the combination meter is connected to the control circuit section 302 through a signal cable 313, so that data of driving signals are supplied from the control circuit section 302 to the drive circuit 313d. 
The control circuit section 302 receives signals of vehicle speed, engine revolution speed, cooling water temperature, and remaining fuel quantity through electrical wires 341 to 344 from sensors (not shown) each desirably positioned in the vehicle. Based on the signals, driving data is supplied to the combination meter main body 301 through a signal cable 303.
FIGS. 11 and 12 are respectively a sectional view and a block diagram showing a configuration of a vehicle mounted combination meter disclosed in Japanese patent application laid-open No. 2001-356031. In FIG. 11, the combination meter has an indicator board 401, a vehicle speed meter 402, a tachometer 405, a fuel meter 408 indicating a remaining quantity of fuel such as gasoline, and a water temperature meter 411. Each meter is attached on a fore surface 401a of the indicator board 401.
The vehicle speed meter 402 is constituted by a stepper motor 403 and a pointer 404. The stepper motor 403 moves the pointer 404 in response to data of vehicle speed. The tachometer 405 is constituted by a stepper motor 406 and a pointer 407. The stepper motor 406 moves the pointer 407 in response to data of engine revolution speed. The fuel meter 408 is constituted by a fuel meter 409 and a pointer 410. The fuel meter 409 moves the pointer 410 in response to data of remaining fuel quantity. The water temperature meter 411 is constituted by a stepper motor 406 and a pointer 407. The stepper motor 406 moves the pointer 407 in response to data of cooling water temperature. Between each stepper motor and each pointer, there is disposed a dial plate (not shown) provided with scales, numerals, letters, or symbols to complete the meter.
In the combination meter, the vehicle speed meter 402 is connected to an infrared receiver element 414 via a stepper motor driver and infrared commutation IC 415; the tachometer 405 is connected to an infrared receiver element 416 via a stepper motor driver and commutation IC 417; the fuel meter 408 is connected to an infrared receiver element 418 via a stepper motor driver and infrared commutation IC 419; and the water temperature meter 411 is connected to an infrared receiver element 420 via a stepper motor driver and infrared commutation IC 421.
The combination meter also has a control module 422 attached on a rear surface 1b of the indication board 430. The control module 422 includes a base board on which there are disposed an IC 424 (including an interface IC 424b, a micro computer IC 424c, and an infrared commutation IC 424d) and an infrared emitting element 425 connected to each other. The IC 424 has an interface IC 424b, a micro computer IC 424c, and an infrared commutation IC 424d. The control module 422 is detachably mounted on the indicator board 401 with two fasteners 423.
In FIG. 12, an input terminal 424a receives values, for example of serial data, measured by various sensors (not shown) in regard to vehicle speed, engine revolution speed, fuel temperature, and engine room temperature. The measured values are input in the micro computer IC 424c via the interface circuit 424b. The micro computer IC 424c processes the measured values to generate data having identification codes. The data is input into the infrared communication IC 424d and transmitted from the infrared emitting element 425 as infrared signals.
The infrared signals transmitted from the infrared emitting element 425 are received by infrared receiver elements 414, 416, 418, and 420 to be supplied into the stepper motor driver and infrared commutation ICs 415, 417, 419, and 421 of the stepper motors. Each of stepper motor driver and infrared commutation ICs 415, 417, 419, and 421 selectively provides each data of vehicle speed, engine revolution speed, fuel quantity, and engine room temperature to each of the vehicle speed meter 402, the tachometer 405, the fuel meter 408, and the water temperature meter 411 together with an identification code.
Thus, the control module 422 is a control section that controls the various types of meters indicating measured values of the vehicle. The control module control module 422 is commonly used for the meters. The control module 422 outputs infrared commutation signals. On the indicator board 401, there are mounted the infrared receiver elements and the infrared commutation ICs of the meters.
The stepper motors 403, 406, 409, and 412 of the vehicle speed meter 402, the tachometer 405, the fuel meter 408, and the water temperature meter 411 are respectively connected to the stepper motor driver and infrared commutation ICs 415, 417, 419, and 421, so that the meters are controlled in response to the infrared signals supplied from the control module 422.
FIGS. 13 and 14 are respectively a block diagram and a general constitutional view of a combination meter proposed in Japanese patent application No. 2002-142720. In FIG. 13, the combination meter has a plurality of display units 500 and a control unit 600. The display unit 500 is provided with a receiver 511 for receiving measurement information showing a condition of the vehicle and a driving control device 530 for controlling a driving device 540 in response to the measurement information supplied from the display side receiver 511. The control unit 600 is provided with a transmitter 631 transmitting the measurement information to the plurality of display units 500 and a control device 611a for controlling transmission of the transmitter 631, an additional information storing device 614, a receiver 633, and a warning device 640.
The display unit 500 further has a response signal generating device 550a, a responding device 550b, and a transmitter 514. The response signal generating device 550a generates driving information for the driving device 540 in response to reception of the measurement information. The display side transmitter 514 transmits the driving information to the control unit 600. The control unit 600 further has a receiver 633 and a decision device 611b. The receiver 633 receives the driving information supplied from the display side transmitter 514. The decision device 611b determines whether the driving device 540 can be controlled or not based on comparison of the driving information received by the receiver 633 with the measurement information transmitted from the control device 611a. The control device 611a operates based on the determination of the decision device 611b. 
As shown in FIG. 14, the display units 500 correspond to a vehicle speed meter, a tachometer indicating engine revolution speeds, a fuel meter indicating a remaining fuel quantity, a temperature meter indicating an engine room temperature, etc. The control unit 600 controls indication of all the display units 500.
The combination meters disclosed or proposed as mentioned above have configurations different from each other. However, each of the combination meters has a system configuration designed specifically for each car maker or for each type of cars. Thus, the combination meter requires a special design for each application, increasing a development cost. Or, minimization of the development cost decreases flexibility of meter design. Furthermore, when multi-display design with LEDs is applied for a combination meter, users cannot select freely the design of the combination meter, because the meter is specifically designed for each car.
In view of the above-mentioned situation, the present invention provides a vehicle-mounted meter system having a standardized common part regardless of car types to decrease a manufacturing cost and to improve design flexibility for customization of users.